1. Field of the Invention
The present invention relates to an insertion instrument comprising a curving portion on the distal side of an insertion portion. The present invention also relates to an insertion instrument in which an action portion is provided in an insertion portion extending along a longitudinal axis, and an insertion apparatus comprising this insertion instrument.
2. Description of the Related Art
In general, an insertion apparatus having an elongated insertion portion to be inserted into a specimen, for example, an endoscope is widely used. Such an endoscope has an insertion portion comprising a curving portion at the distal side, and a curving operation portion to curve the curving portion. When such an endoscope is used to, for example, observe and treat, for example, a lesion in the specimen, the curving operation portion is operated to curve the curving portion in a desired direction and insert the curving portion into the specimen at the same time.
For example, Patent Literature 1: International Publication No. 2012/074013 discloses an endoscope provided with, as curving operation portions, a UD curving operation knob for curving a curving portion in an up/down (UD) direction, and an RL curving operation dial for curving the curving portion in a right/left (RL) direction. The UD curving operation knob is provided in an operation portion body of the endoscope along its longitudinal axis, and the RL curving operation dial is provided in the operation portion body in the vicinity of the lower side of the UD curving operation knob. The curving portion is mechanically curved in the UD direction if an operator rotates the UD curving operation knob. The curving portion is curved in the RL direction by driving force from a motor which is driven if the operator rotates the RL curving operation dial. That is, the curving in the RL direction is electrically driven.
For example, Patent Literature 2: Jpn. Pat. Appln. KOKAI Publication No. 2006-320501 discloses an endoscope comprising a curving portion composed of a distal-side first curving portion and a proximal-side second curving portion to insert an insertion portion into a specimen along the bending shape of the specimen. The first curving portion and the second curving portion are respectively curved in the UD direction and the RL direction independently of each other by the rotation operations of a UD curving operation knob and an RL curving operation knob for curving the first curving portion and by the rotation operation of a UD curving operation knob for curving the second curving portion.
In the endoscope disclosed in Patent Literature 1: International Publication No. 2012/074013, a curving portion which is an action portion is provided at the distal end of an insertion portion, and a holding portion is provided closer to the proximal direction side than the insertion portion. The curving portion performs a first action to curve in first perpendicular directions which are two directions perpendicular to a longitudinal axis, and a second action to curve in second perpendicular directions which are two directions perpendicular to the longitudinal axis and perpendicular to a first curving direction. The holding portion comprises a holding portion casing, and a curving operation knob which a first operation input portion rotatable relative to the holding portion casing around a rotation axis perpendicular to the longitudinal axis. The first operation to operate the first action of the curving portion is input by the rotation of the curving operation knob.
Here, one of directions parallel to the rotation axis is a first rotation axis direction, and a direction opposite to the first rotation axis direction is a second rotation axis direction. One of directions perpendicular to the longitudinal axis and perpendicular to the rotation axis is a first perpendicular direction, and a direction opposite to the first perpendicular direction is a second perpendicular direction. A holding portion housing comprises a first casing outer surface which faces in the first rotation axis direction and in which the curving operation knob is disposed, and a second casing outer surface which faces in the first perpendicular direction. A curving operation dial which is a second operation input portion is provided in the second casing outer surface. A second operation to operate the second action of the curving portion is input by the rotation of the curving operation dial around a drive axis. The drive axis extends from the curving operation dial toward the proximal direction side in such a manner as to cross over the rotation axis. The curving operation dial is located closer to the distal direction side than the curving operation knob.
A button unit which comprises operation buttons such as air/liquid supply operation button is provided on the second casing outer surface. In a longitudinal axis direction parallel to the longitudinal axis, the position of the button unit substantially corresponds to the position of the curving operation knob. Paths such as an air supply path and a liquid supply path extend through the holding portion, and air/liquid valves are disposed as functional units in the air supply path and the liquid supply path. A switch operation to switch on and off (the operation states of) the air/liquid valves in the air supply path and the liquid supply path is input by the air/liquid supply operation button.